Structural Diversity of Silver(I) 4,6-Dipyridyl-2-Aminopyrimidine Complexes:  Effect of Counteranions and Ligand Isomerism

Using two ligands, 4,6-bis(2-pyridyl)-2-aminopyrimidine (L1) with two N,N‘-chelating sites and 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (L2) (as the isomer of L1) containing one chelating site and one bridging unit, a series of novel Ag(I) complexes varying from zero- to two-dimensions have been prepared and their crystal structures determined via single-crystal X-ray diffraction. The two ligands are employed for the first time in coordination chemistry. The structures of compounds 1−3 are directed by the counteranions adopted in the reaction system:  The reaction of L1 with AgNO₃ yielded a dimer [Ag₂L1₂](NO₃)₂ (1). The reaction of L1 with AgCF₃SO₃ led to a one-dimension “V-shaped” chain {[AgL1](CF₃SO₃)}_n (2). When AgSCN was used, a one-dimension ladder {[Ag₂L1(SCN)₂]·H₂O}_n (3) was obtained. While ligand L2 reacted with AgNO₃, a two-dimension {[Ag₂(L2)₂](NO₃)₂·H₂O}_n (4) was prepared with the help of an argentophilic interaction. Compounds 1−4 display room-temperature photoluminescence.